New river gauge bumps up historical river crests

Historical river crests, flood stages and impact levels for the community of Granite Falls have all been bumped up six inches as a result of the installation of an automated river gauge.This past summer the City of Granite Falls, with the aid of a DNR flood mitigation dollars, commissioned the U.S. Geological Surve...

Historical river crests, flood stages and impact levels for the community of Granite Falls have all been bumped up six inches as a result of the installation of an automated river gauge.

This past summer the City of Granite Falls, with the aid of a DNR flood mitigation dollars, commissioned the U.S. Geological Survey (USGS) to install the automated river gauge below the 212 Bridge to allow for the collection of timely, up-to-date river level information.

The USGS installed the device utilizing new data reference points (NAVD88 as opposed to NVGD29), which alter the river flood stages, historical crests and impact levels to the tune of a .54 foot increase, according to National Weather Service Hydrologist Diane Cooper.

For simplicity's sake, the adjustments have been rounded to .5 feet for both flood stages and impact levels. Below are the new historical crests, flood stage and impact levels as a result of the change in reference points.